CAM35C44 datasheet(28/50 Pages) SMSC

28 / 50 page

Transmitter Auto Power Down

The UART transmitter is powered down from the

auto power down state when the transmit buffer

and transmit shift registers are empty.

Receiver Auto Power Down

The UART receiver is powered down from the

auto power state when the receive FIFO is

empty and the receiver is waiting for a start bit.

Ring Indicator Auto Power Down

When the UART is powered down from the auto

power state, a Ring Indicator interrupt can occur

on active transitions of the Ring Indicator input

nRI.

Exit Auto Power Down

The transmitter exits the auto power down state

on a write to the transmit buffer. The receiver

exits the auto power down state when the

receiver input RXD changes state.

TABLE 24 - ACE UART POWER STATES

ACE_ON

(D1)

AUTO_PWR

(D4)

DESCRIPTION

ACE POWER OFF

ACE POWER ON

ACE AUTO POWER DOWN

INT_OSC, Bit 5

The INT_ OSC bit D5 selects the clock source

for the CAM35C44 clock generator (see section

CLOCK

GENERATOR

page

12).

When INT_OSC is “0” (default), the clock

generator is driven by an external clock source.

When INT_OSC is “1”, the clock generator is

driven by the internal crystal oscillator.

CAM35C44 Datasheet(PDF) 28 Page - SMSC Corporation